Yellow Nails: 6 Common Causes & What to Do

Updated in December 2022

Yellow nails mainly occur as a result of a fungal nail infection. These infections can alter the shape, texture and color of fingernails or toenails.

However, yellow nails can also be a result of normal aging, smoking or a nutritional deficiency, like a lack of vitamin A or vitamin C. 

Yellow nails may be a sign of a health condition, like ungual psoriasis, and therefore you should report this finding to your doctor. The doctor will assess the affected nails as well as other symptoms to determine whether further treatment is required. 

Imagem ilustrativa número 1

What causes yellowing?

The main causes of yellow nails are:

1. Fungal infection

Fungal nail infections, or onychomycosis, can cause changes to the color, shape or texture of the nail. Nail fungus often leaves finger or toenails thicker, deformed and yellow. This infection can be transmitted at the pool or in public locker rooms, where people are prone to walk barefoot. They can also be transmitted at nail salons through shared manicure tools. 

What to do: Nail fungus can be treated with antifungal nail polishes or oral medications, which are used as directed by a dermatologist. 

2. Vitamin or mineral deficiency

Nutritional deficiencies can leave many parts of the body, as well as the nails, more fragile, breaking and discolored. Yellow nails can be a result of a lack of antioxidants, like vitamin A or vitamin C. 

What to do: Ideally, you should maintain a healthy, varied diet to prevent a vitamin or mineral deficiency. If necessary, a doctor or registered dietitian may recommend vitamin supplements, to be taken for at least 3 months. 

3. Normal aging

As we get older, our nails become weaker and can become slightly more yellow. This is a natural aging process and does not indicate any health problems. 

What to do: Applying hydrogen peroxide is a great way to brighten the nails. To make them stronger, you can apply a strengthening nail lacquer.

4. Using nail polish 

Frequently using nail polish, particularly bright colors like red or orange, or keeping nail polish on the nails for a long time can give the nails a yellow color. 

What to do: To prevent yellowing of the nails from nail polish, you should alternate periods of nail polish use with periods of bare nails. You should also use a base polish to protect the nail before applying a color polish. 

5. Ungual psoriasis

Ungual psoriasis occurs when the body’s defense cells attack the finger or toenails. This can leave the nails wavy in texture, deformed, fragile, thick and spotted. 

What to do: Although psoriasis is not curable, nail appearance can be improved with nail polishes that contain clobetasol and vitamin D. Some other home treatments may include hydrating the nails regularly and maintaining a diet that is rich in omega-3 foods, like flaxseeds, salmon and tuna.

6. Smoking

Smoking can increase the risk for many diseases, like bronchitis or emphysema, due to its high concentration of toxic substances, like nicotine. Nicotine can penetrate the skin, particularly the fingers and fingernails, and cause them to turn yellow. 

What to do: Although there are treatments that can help brighten the nails, you are advised to stop smoking. This will help to improve nail and skin appearance and also the risk for developing more serious health conditions.